Chromium and chromium alloy thin films are useful in semiconductor manufacturing processes. For example, chromium alloy thin film resistors are used in integrated circuits and chromium and chromium alloy thin films are used in the fabrication of photo masks.
Chromium alloys are difficult to dry etch. Wet etches for chromium are used when dimension control is not critical. When dimension control is critical, plasma etches such as reactive ion etching (RIE) are used. Typically these etches utilize significant ion bombardment to physically sputter away much of the film. Chromium alloy RIE etches are typically slow and typically deposit residue on the walls of the etching chamber walls that may require frequent cleaning. Linewidth control on critical geometries may also be difficult with physically sputtered thin films